Requiem shark

The common name requiem shark may be related to the French word for shark, , which is itself of disputed etymology. One derivation of the latter is from Latin requiem ("rest"), which would thereby create a cyclic etymology (requiem-requin-requiem), but other sources derive it from the Old French verb reschignier ("to grimace while baring teeth"). The scientific name Carcharhinidae was first proposed in 1896 by D.S. Jordan and B.W. Evermann as a subfamily of Galeidae (now replaced by "Carcharhinidae"). The term is derived from Greek (karcharos, sharp or jagged), and ῥί̄νη (rhinē, rasp); both elements describe the jagged, rasp-like skin. Rasp-like skin is typical of shark skin in general, and is not diagnostic to Carcharhinidae. == Evolutionary history ==

The oldest member of the family is Archaeogaleus lengadocensis from the Early Cretaceous (Valanginian) of France. Only a handful of records of the group are known from prior to the beginning of the Cenozoic. Modern carcharinid sharks have extensively diversified in coral reef habitats. == Hunting strategies ==

Requiem sharks are extraordinarily fast and effective hunters. Their elongated, torpedo-shaped bodies make them quick and agile swimmers, so they can easily attack any prey. Some species are continually active, while others are capable of resting motionless for extended periods on the bottom. They have a range of food sources depending on location and species, including bony fish, squid, octopus, lobster, turtles, marine mammals, seabirds, other sharks and rays; smaller species tend to select a narrow range of prey, but some very large species, especially the tiger shark (Galeocerdo cuvier), are virtually omnivorous. They are often considered the "garbage cans" of the seas because they will eat almost anything, even non-food items like trash. They are migratory hunters that follow their food source across entire oceans. They tend to be most active at night time, where their impressive eyesight can help them sneak up on unsuspecting prey. It is worth mentioning that the tiger shark belongs to the Galeocerdo family. Most requiem sharks hunt alone, however some species like the whitetip reef sharks and lemon sharks are cooperative feeders and will hunt in packs through coordinated, timed attacks against their prey. Some of the species have been shown to give specialized displays when confronted by divers or other sharks, which may be indicative of aggressive or defensive threat. ==Classification==

The 60 species of requiem shark are grouped into 10 genera: • Carcharhinus tjutjot Bleeker, 1852 (Indonesian whaler shark) • †?Carcharhinus obsolerus White, Kyne, and Harris, 2019 (lost shark) • Genus Glyphis Agassiz, 1843 • Glyphis gangeticus J. P. Müller & Henle, 1839 (Ganges shark) • Glyphis garricki Compagno, W. T. White & Last, 2008 (northern river shark) • Glyphis glyphis J. P. Müller & Henle, 1839 (speartooth shark) • Glyphis sp. not yet described (Mukah river shark) • Genus Lamiopsis Gill, 1862 • Lamiopsis temminckii J. P. Müller & Henle, 1839 (broadfin shark) • Lamiopsis tephrodes Fowler, 1905 (Borneo broadfin shark) • Genus Nasolamia Compagno & Garrick, 1983 • Nasolamia velox C. H. Gilbert, 1898 (whitenose shark) • Genus Negaprion Whitley, 1940 • , Negaprion brevirostris, at Tiger Beach, BahamasNegaprion acutidens Rüppell, 1837 (sicklefin lemon shark) • Negaprion brevirostris Poey, 1868 (lemon shark) • †Negaprion eurybathrodon Blake, 1862 • Genus Prionace Cantor, 1849 • , Prionace glaucaPrionace glauca Linnaeus, 1758 (blue shark) • Genus Rhizoprionodon Whitley, 1929 • Rhizoprionodon acutus Rüppell, 1837 (milk shark) • Rhizoprionodon lalandii J. P. Müller & Henle, 1839 (Brazilian sharpnose shark) • Rhizoprionodon longurio D. S. Jordan & C. H. Gilbert, 1882 (Pacific sharpnose shark) • Rhizoprionodon oligolinx V. G. Springer, 1964 (grey sharpnose shark) • Rhizoprionodon porosus Poey, 1861 (Caribbean sharpnose shark) • Rhizoprionodon taylori Ogilby, 1915 (Australian sharpnose shark) • Rhizoprionodon terraenovae J. Richardson, 1836 (Atlantic sharpnose shark) • Genus Loxodon J. P. Müller & Henle, 1838 • Loxodon macrorhinus J. P. Müller & Henle, 1839 (sliteye shark) • Genus Triaenodon J. P. Müller & Henle, 1837 • Triaenodon obesus Rüppell, 1837 (whitetip reef shark) ==See also==